Break out the "Backup" disucssion from HW to general sysadmin.
Create "Disks" section to discuss ways of adding drives.
This commit is contained in:
David E. O'Brien
parent
1ff7581efd
commit
d07e465d9e
Notes:
svn2git
2020-12-08 03:00:23 +00:00
svn path=/head/; revision=2757
6 changed files with 616 additions and 545 deletions
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@ -1,10 +1,10 @@
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# $Id: Makefile,v 1.30 1998-03-15 15:10:01 nik Exp $
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# $Id: Makefile,v 1.31 1998-04-30 10:31:00 obrien Exp $
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SGMLOPTS=-links
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SRCS= authors.sgml basics.sgml bibliography.sgml boothelp.sgml
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SRCS= authors.sgml backups.sgml basics.sgml bibliography.sgml boothelp.sgml
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SRCS+= booting.sgml contrib.sgml crypt.sgml ctm.sgml current.sgml cvsup.sgml
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SRCS+= cyclades.sgml development.sgml dialup.sgml dialout.sgml
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SRCS+= diskless.sgml dma.sgml eresources.sgml esdi.sgml
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SRCS+= disks.sgml diskless.sgml dma.sgml eresources.sgml esdi.sgml
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SRCS+= firewalls.sgml german.sgml glossary.sgml goals.sgml
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SRCS+= handbook.sgml history.sgml hw.sgml install.sgml isdn.sgml
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SRCS+= kerberos.sgml kernelconfig.sgml kerneldebug.sgml kernelopts.sgml
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570
handbook/backups.sgml
Normal file
570
handbook/backups.sgml
Normal file
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@ -0,0 +1,570 @@
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<!-- $Id: backups.sgml,v 1.1 1998-04-30 10:31:01 obrien Exp $ -->
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<!-- The FreeBSD Documentation Project -->
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<!--
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<!DOCTYPE chapt PUBLIC "-//FreeBSD//DTD linuxdoc//EN"> -->
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<chapt><heading>Backups<label id="backups"></heading>
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<p>Issues of hardware compatibility are among the most
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troublesome in the computer industry today and FreeBSD is by
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no means immune to trouble. In this respect, FreeBSD's
|
||||
advantage of being able to run on inexpensive commodity PC
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hardware is also its liability when it comes to support for
|
||||
the amazing variety of components on the market. While it
|
||||
would be impossible to provide a exhaustive listing of
|
||||
hardware that FreeBSD supports, this section serves as a
|
||||
catalog of the device drivers included with FreeBSD and the
|
||||
hardware each drivers supports. Where possible and
|
||||
appropriate, notes about specific products are included.
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You may also want to refer to <ref id="kernelconfig:config"
|
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name="the kernel configuration file"> section in this handbook for
|
||||
a list of supported devices.
|
||||
|
||||
As FreeBSD is a volunteer project without a funded testing
|
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department, we depend on you, the user, for much of the
|
||||
information contained in this catalog. If you have direct
|
||||
experience of hardware that does or does not work with
|
||||
FreeBSD, please let us know by sending e-mail to the &a.doc;.
|
||||
Questions about supported hardware
|
||||
should be directed to the &a.questions (see
|
||||
<ref id="eresources:mail" name="Mailing Lists"> for more
|
||||
information). When submitting information or asking a
|
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question, please remember to specify exactly what version of
|
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FreeBSD you are using and include as many details of your
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hardware as possible.
|
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|
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<sect><heading>* What about backups to floppies?</heading>
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<sect><heading> Tape Media<label id="backups:tapebackups"></heading>
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<p>The major tape media are the 4mm, 8mm, QIC, mini-cartridge and
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DLT.
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<sect1><heading> 4mm (DDS: Digital Data Storage)
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<label id="backups:tapebackups:4mm"></heading>
|
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<!--gen-->
|
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<p>4mm tapes are replacing QIC as the workstation backup
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media of choice. This trend accelerated greatly when Conner
|
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purchased Archive, a leading manufacturer of QIC drives, and then
|
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stopped production of QIC drives. 4mm drives are small and quiet
|
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but do not have the reputation for reliability that is enjoyed by 8mm drives.
|
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The cartridges are less expensive and smaller (3 x 2 x 0.5
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inches, 76 x 51 x 12 mm) than 8mm cartridges. 4mm, like 8mm, has
|
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comparatively short head life for the same reason, both use
|
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helical scan.
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|
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<!--spec-->
|
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<p>Data thruput on these drives starts ~150kB/s, peaking
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at ~500kB/s. Data capacity starts at 1.3 GB and ends at 2.0 GB.
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Hardware compression, available with most of these drives,
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approximately doubles the capacity. Multi-drive tape library
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units can have 6 drives in a single cabinet with automatic tape
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changing. Library capacities reach 240 GB.
|
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|
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<!--tech-->
|
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<p>4mm drives, like 8mm drives, use helical-scan. All
|
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the benefits and drawbacks of helical-scan apply to both 4mm and
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8mm drives.
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|
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<p>Tapes should be retired from use after 2,000 passes or
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100 full backups.
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|
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<sect1><heading> 8mm (Exabyte)<label id="backups:tapebackups:8mm">
|
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</heading>
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|
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<!--gen-->
|
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<p>8mm tapes are the most common SCSI tape drives; they
|
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are the best choice of exchanging tapes. Nearly every site has
|
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an exabyte 2 GB 8mm tape drive. 8mm drives are reliable,
|
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convenient and quiet. Cartridges are inexpensive and small (4.8 x
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3.3 x 0.6 inches; 122 x 84 x 15 mm). One downside of 8mm tape is
|
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relatively short head and tape life due to the high rate of
|
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relative motion of the tape across the heads.
|
||||
|
||||
<!--spec-->
|
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<p>Data thruput ranges from ~250kB/s to ~500kB/s. Data
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sizes start at 300 MB and go up to 7 GB. Hardware compression,
|
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available with most of these drives, approximately doubles the
|
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capacity. These drives are available as single units or
|
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multi-drive tape libraries with 6 drives and 120 tapes in a
|
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single cabinet. Tapes are changed automatically by the unit.
|
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Library capacities reach 840+ GB.
|
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|
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<!--tech-->
|
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<p>Data is recorded onto the tape using helical-scan, the
|
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heads are positioned at an angle to the media (approximately 6
|
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degrees). The tape wraps around 270 degrees of the spool that
|
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holds the heads. The spool spins while the tape slides over the
|
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spool. The result is a high density of data and closely packed
|
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tracks that angle across the tape from one edge to the other.
|
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|
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|
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<sect1><heading> QIC<label id="backups:tapebackups:qic"></heading>
|
||||
<!--gen-->
|
||||
<p>QIC-150 tapes and drives are, perhaps, the most common
|
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tape drive and media around. QIC tape drives are the least
|
||||
expensive "serious" backup drives. The downside is the cost of
|
||||
media. QIC tapes are expensive compared to 8mm or 4mm tapes, up
|
||||
to 5 times the price per GB data storage. But, if your needs can
|
||||
be satisfied with a half-dozen tapes, QIC may be the correct
|
||||
choice. QIC is the <em>most</em> common tape drive. Every site
|
||||
has a QIC drive of some density or another. Therein lies the
|
||||
rub, QIC has a large number of densities on physically similar
|
||||
(sometimes identical) tapes. QIC drives are not quiet. These
|
||||
drives audibly seek before they begin to record data and are
|
||||
clearly audible whenever reading, writing or seeking. QIC tapes
|
||||
measure (6 x 4 x 0.7 inches; 15.2 x 10.2 x 1.7 mm). <ref
|
||||
id="backups:tapebackups:mini" name="Mini-cartridges">, which also
|
||||
use 1/4" wide tape are discussed separately. Tape libraries and
|
||||
changers are not available.
|
||||
|
||||
<!--spec-->
|
||||
<p>Data thruput ranges from ~150kB/s to ~500kB/s. Data
|
||||
capacity ranges from 40 MB to 15 GB. Hardware compression is
|
||||
available on many of the newer QIC drives. QIC drives are less
|
||||
frequently installed; they are being supplanted by DAT drives.
|
||||
|
||||
<!--tech-->
|
||||
<p>Data is recorded onto the tape in tracks. The tracks
|
||||
run along the long axis of the tape media from one end to the
|
||||
other. The number of tracks, and therefore the width of a track,
|
||||
varies with the tape's capacity. Most if not all newer drives
|
||||
provide backward-compatibility at least for reading (but often
|
||||
also for writing). QIC has a good reputation regarding the
|
||||
safety of the data (the mechanics are simpler and more robust
|
||||
than for helical scan drives).
|
||||
|
||||
<p>Tapes should be retired from use after 5,000 backups.
|
||||
|
||||
<sect1><heading> * Mini-Cartridge<label id="backups:tapebackups:mini">
|
||||
</heading>
|
||||
|
||||
<sect1><heading> DLT<label id="backups:tapebackups:dlt"></heading>
|
||||
<!--gen-->
|
||||
<p>DLT has the fastest data transfer rate of all the drive
|
||||
types listed here. The 1/2" (12.5mm) tape is contained in a
|
||||
single spool cartridge (4 x 4 x 1 inches; 100 x 100 x 25 mm). The
|
||||
cartridge has a swinging gate along one entire side of the
|
||||
cartridge. The drive mechanism opens this gate to extract the
|
||||
tape leader. The tape leader has an oval hole in it which the
|
||||
drive uses to "hook" the tape. The take-up spool is located
|
||||
inside the tape drive. All the other tape cartridges listed here
|
||||
(9 track tapes are the only exception) have both the supply and
|
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take-up spools located inside the tape cartridge itself.
|
||||
|
||||
<!--spec-->
|
||||
Data thruput is approximately 1.5MB/s, three times the
|
||||
thruput of 4mm, 8mm, or QIC tape drives. Data capacities range
|
||||
from 10GB to 20GB for a single drive. Drives are available in
|
||||
both multi-tape changers and multi-tape, multi-drive tape
|
||||
libraries containing from 5 to 900 tapes over 1 to 20 drives,
|
||||
providing from 50GB to 9TB of storage.
|
||||
|
||||
<!--tech-->
|
||||
Data is recorded onto the tape in tracks parallel to the
|
||||
direction of travel (just like QIC tapes). Two tracks are written
|
||||
at once. Read/write head lifetimes are relatively long; once the
|
||||
tape stops moving, there is no relative motion between the heads
|
||||
and the tape.
|
||||
|
||||
<sect1><heading> Using a new tape for the first time</heading>
|
||||
<p>The first time that you try to read or write a new,
|
||||
completely blank tape, the operation will fail. The console
|
||||
messages should be similar to:
|
||||
<tscreen><verb>
|
||||
st0(ncr1:4:0): NOT READY asc:4,1
|
||||
st0(ncr1:4:0): Logical unit is in process of becoming ready
|
||||
</verb></tscreen>
|
||||
|
||||
The tape does not contain an Identifier Block (block number
|
||||
0). All QIC tape drives since the adoption of QIC-525 standard
|
||||
write an Identifier Block to the tape. There are two
|
||||
solutions:
|
||||
<p><tt>mt fsf 1</tt> causes the tape drive to write an
|
||||
Identifier Block to the tape.
|
||||
<p>Use the front panel button to eject the tape.
|
||||
<p>Re-insert the tape and <tt>dump(8)</tt> data to the
|
||||
tape.
|
||||
<p><tt>dump(8)</tt> will report <tt>DUMP: End of tape
|
||||
detected</tt> and the console will show: <tt>HARDWARE FAILURE
|
||||
info:280 asc:80,96</tt>
|
||||
<p>rewind the tape using: <tt>mt rewind</tt>
|
||||
|
||||
<p>Subsequent tape operations are successful.
|
||||
|
||||
<sect><heading> Backup Programs<label id="backup:programs"></heading>
|
||||
<p>The three major programs are <tt>dump(8)</tt>,
|
||||
<tt>tar(1)</tt>, and <tt>cpio(1)</tt>.
|
||||
|
||||
<sect1><heading> Dump and Restore</heading>
|
||||
<!--gen-->
|
||||
<p><tt>dump(8)</tt> and <tt>restore(8)</tt> are the
|
||||
traditional Unix backup programs. They operate on the drive as a
|
||||
collection of disk blocks, below the abstractions of files, links
|
||||
and directories that are created by the filesystems.
|
||||
<tt>dump(8)</tt> backs up devices, entire filesystems, not parts
|
||||
of a filesystem and not directory trees that span more than one
|
||||
filesystem, using either soft links <tt>ln(1)</tt> or mounting
|
||||
one filesystem onto another. <tt>dump(8)</tt> does not write
|
||||
files and directories to tape, but rather writes the data blocks
|
||||
that are the building blocks of files and directories.
|
||||
<tt>dump(8)</tt> has quirks that remain from its early days in
|
||||
Version 6 of ATT Unix (circa 1975). The default parameters are
|
||||
suitable for 9-track tapes (6250 bpi), not the high-density media
|
||||
available today (up to 62,182 ftpi). These defaults must be
|
||||
overridden on the command line to utilize the capacity of current
|
||||
tape drives.
|
||||
|
||||
<p><tt>rdump(8)</tt> and <tt>rrestore(8)</tt> backup data
|
||||
across the network to a tape drive attached to another computer.
|
||||
Both programs rely upon <tt>rcmd(3)</tt> and <tt>ruserok(3)</tt>
|
||||
to access the remote tape drive. Therefore, the user performing
|
||||
the backup must have <tt>rhosts</tt> access to the remote
|
||||
computer. The arguments to <tt>rdump(8)</tt> and
|
||||
<tt>rrestore(8)</tt> must suitable to use on the remote computer.
|
||||
(e.g. When <tt>rdump</tt>'ing from a FreeBSD computer to an
|
||||
Exabyte tape drive connected to a Sun called komodo, use: <tt>/sbin/rdump
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||||
0dsbfu 54000 13000 126 komodo:/dev/nrst8 /dev/rsd0a 2>&1</tt>)
|
||||
Beware: there are security implications to allowing
|
||||
<tt>rhosts</tt> commands. Evaluate your situation carefully.
|
||||
|
||||
|
||||
|
||||
<sect1><heading> Tar</heading>
|
||||
<!--gen-->
|
||||
<p><tt>tar(1)</tt> also dates back to Version 6 of ATT
|
||||
Unix (circa 1975). <tt>tar(1)</tt> operates in cooperation with
|
||||
the filesystem; <tt>tar(1)</tt> writes files and directories to
|
||||
tape. <tt>tar(1)</tt> does not support the full range of options
|
||||
that are available from <tt>cpio(1)</tt>, but <tt>tar(1)</tt>
|
||||
does not require the unusual command pipeline that
|
||||
<tt>cpio(1)</tt> uses.
|
||||
|
||||
<p>Most versions of <tt>tar(1)</tt> do not support backups across the
|
||||
network. The GNU version of <tt>tar(1)</tt>, which FreeBSD utilizes, supports
|
||||
remote devices using the same syntax as <tt>rdump</tt>. To <tt>tar(1)</tt>
|
||||
to an Exabyte tape drive connected to a Sun called komodo, use:
|
||||
<tt>/usr/bin/tar cf komodo:/dev/nrst8 . 2>&1</tt>.
|
||||
For versions without remote device support, you can use a pipeline
|
||||
and <tt>rsh(1)</tt> to send the
|
||||
data to a remote tape drive. (XXX add an example command)
|
||||
|
||||
<sect1><heading> Cpio</heading>
|
||||
<!--gen-->
|
||||
<p><tt>cpio(1)</tt> is the original Unix file interchange
|
||||
tape program for magnetic media. <tt>cpio(1)</tt> has options (among
|
||||
many others) to perform byte-swapping, write a number of
|
||||
different archives format, and pipe the data to other programs.
|
||||
This last feature makes <tt>cpio(1)</tt> and excellent choice for
|
||||
installation media. <tt>cpio(1)</tt> does not know how to walk
|
||||
the directory tree and a list of files must be provided thru <tt>STDIN</tt>.
|
||||
|
||||
<p><tt>cpio(1)</tt> does not support backups across the
|
||||
network. You can use a pipeline and <tt>rsh(1)</tt> to send the
|
||||
data to a remote tape drive. (XXX add an example command)
|
||||
|
||||
<sect1><heading> Pax</heading>
|
||||
<!--gen-->
|
||||
|
||||
<p><tt>pax(1)</tt> is IEEE/POSIX's answer to <tt>tar</tt> and
|
||||
<tt>cpio</tt>. Over the years the various versions of <tt>tar</tt> and
|
||||
<tt>cpio</tt> have gotten slightly incompatible. So rather than fight it
|
||||
out to fully standardize them, POSIX created a new archive utility.
|
||||
<tt>pax</tt> attempts to read and write many of the various cpio and tar
|
||||
formats, plus new formats of its own. Its command set more resembles
|
||||
<tt>cpio</tt> than <tt>tar</tt>.
|
||||
|
||||
|
||||
<sect1><heading> Amanda<label id="backups:programs:amanda"></heading>
|
||||
<p><htmlurl url="http://www.freebsd.org/ports/misc.html#amanda-2.4.0"
|
||||
name="Amanda"> (Advanced Maryland Network Disk Archiver) is a
|
||||
client/server backup system, rather than a single program. An
|
||||
Amanda server will backup to a single tape drive any number of
|
||||
computers that have Amanda clients and network communications
|
||||
with the Amanda server. A common problem at locations with a
|
||||
number of large disks is the length of time required to backup to
|
||||
data directly to tape exceeds the amount of time available for
|
||||
the task. Amanda solves this problem. Amanda can use a "holding
|
||||
disk" to backup several filesystems at the same time. Amanda
|
||||
creates "archive sets": a group of tapes used over a period of
|
||||
time to create full backups of all the filesystems listed in
|
||||
Amanda's configuration file. The "archive set" also contains
|
||||
nightly incremental (or differential) backups of all the
|
||||
filesystems. Restoring a damaged filesystem requires the most
|
||||
recent full backup and the incremental backups.
|
||||
|
||||
<p>The configuration file provides fine control backups
|
||||
and the network traffic that Amanda generates. Amanda will use
|
||||
any of the above backup programs to write the data to tape.
|
||||
Amanda is available as either a port or a package, it is not
|
||||
installed by default.
|
||||
|
||||
<sect1><heading> Do nothing</heading>
|
||||
<p>"Do nothing" is not a computer program, but it is the
|
||||
most widely used backup strategy. There are no initial costs.
|
||||
There is no backup schedule to follow. Just say no. If
|
||||
something happens to your data, grin and bear it!
|
||||
|
||||
<p>If your time and your data is worth little to nothing,
|
||||
then "Do nothing" is the most suitable backup program for your
|
||||
computer. But beware, Unix is a useful tool, you may find that
|
||||
within six months you have a collection of files that are
|
||||
valuable to you.
|
||||
|
||||
<p>"Do nothing" is the correct backup method for
|
||||
<tt>/usr/obj</tt> and other directory trees that can be exactly
|
||||
recreated by your computer. An example is the files that
|
||||
comprise these handbook pages-they have been generated from
|
||||
<tt>SGML</tt> input files. Creating backups of these
|
||||
<tt>HTML</tt> files is not necessary. The <tt>SGML</tt> source
|
||||
files are backed up regularly.
|
||||
|
||||
<sect1><heading> Which Backup Program is Best?</heading>
|
||||
<p><tt>dump(8)</tt> <em>Period.</em> Elizabeth D. Zwicky
|
||||
torture tested all the backup programs discussed here. The clear
|
||||
choice for preserving all your data and all the peculiarities of
|
||||
Unix filesystems is <tt>dump(8)</tt>. Elizabeth created
|
||||
filesystems containing a large variety of unusual conditions (and
|
||||
some not so unusual ones) and tested each program by do a backup
|
||||
and restore of that filesystems. The peculiarities included:
|
||||
files with holes, files with holes and a block of nulls, files
|
||||
with funny characters in their names, unreadable and unwritable
|
||||
files, devices, files that change size during the backup, files
|
||||
that are created/deleted during the backup and more. She
|
||||
presented the results at LISA V in Oct. 1991.
|
||||
|
||||
<sect1><heading>Emergency Restore Procedure</heading>
|
||||
<sect2><heading> Before the Disaster</heading>
|
||||
<p>There are only four steps that you need to perform in
|
||||
preparation for any disaster that may occur.
|
||||
|
||||
<p>First, print the disklabel from each of your disks
|
||||
(<tt>e.g. disklabel sd0 | lpr</tt>), your filesystem table
|
||||
(<tt>/etc/fstab</tt>) and all boot messages, two copies of each.
|
||||
|
||||
<p>Second, determine the boot and fixit floppies
|
||||
(boot.flp and fixit.flp) have all your devices. The easiest way
|
||||
to check is to reboot your machine with the boot floppy in the
|
||||
floppy drive and check the boot messages. If all your devices
|
||||
are listed and functional, skip on to step three.
|
||||
|
||||
<p>Otherwise, you have to create two custom bootable
|
||||
floppies which has a kernel that can mount your all of your disks
|
||||
and access your tape drive. These floppies must contain:
|
||||
<tt>fdisk(8)</tt>, <tt>disklabel(8)</tt>, <tt>newfs(8)</tt>,
|
||||
<tt>mount(8)</tt>, and whichever backup program you use. These
|
||||
programs must be statically linked. If you use <tt>dump(8)</tt>,
|
||||
the floppy must contain <tt>restore(8)</tt>.
|
||||
|
||||
<p>Third, create backup tapes regularly.
|
||||
Any changes that you make after your last backup may be
|
||||
irretrievably lost. Write-protect the backup tapes.
|
||||
|
||||
<p>Fourth, test the floppies (either boot.flp and
|
||||
fixit.flp or the two custom bootable floppies you made in step
|
||||
two.) and backup tapes. Make notes of the procedure. Store
|
||||
these notes with the bootable floppy, the printouts and the
|
||||
backup tapes. You will be so distraught when restoring that the
|
||||
notes may prevent you from destroying your backup tapes (How? In
|
||||
place of <tt>tar xvf /dev/rst0</tt>, you might accidently type
|
||||
<tt> tar cvf /dev/rst0</tt> and over-write your backup tape).
|
||||
|
||||
<p>For an added measure of security, make bootable
|
||||
floppies and two backup tapes each time. Store one of each at a
|
||||
remote location. A remote location is NOT the basement of the
|
||||
same office building. A number of firms in the World Trade Center
|
||||
learned this lesson the hard way. A remote location should be
|
||||
physically separated from your computers and disk drives by a
|
||||
significant distance.
|
||||
|
||||
<p>An example script for creating a bootable floppy:
|
||||
<tscreen><verb>
|
||||
#!/bin/sh
|
||||
#
|
||||
# create a restore floppy
|
||||
#
|
||||
# format the floppy
|
||||
#
|
||||
PATH=/bin:/sbin:/usr/sbin:/usr/bin
|
||||
|
||||
fdformat -q fd0
|
||||
if [ $? -ne 0 ]
|
||||
then
|
||||
echo "Bad floppy, please use a new one"
|
||||
exit 1
|
||||
fi
|
||||
|
||||
# place boot blocks on the floppy
|
||||
#
|
||||
disklabel -w -B -b /usr/mdec/fdboot -s /usr/mdec/bootfd /dev/rfd0c fd1440
|
||||
|
||||
#
|
||||
# newfs the one and only partition
|
||||
#
|
||||
newfs -t 2 -u 18 -l 1 -c 40 -i 5120 -m 5 -o space /dev/rfd0a
|
||||
|
||||
#
|
||||
# mount the new floppy
|
||||
#
|
||||
mount /dev/fd0a /mnt
|
||||
|
||||
#
|
||||
# create required directories
|
||||
#
|
||||
mkdir /mnt/dev
|
||||
mkdir /mnt/bin
|
||||
mkdir /mnt/sbin
|
||||
mkdir /mnt/etc
|
||||
mkdir /mnt/root
|
||||
mkdir /mnt/mnt # for the root partition
|
||||
mkdir /mnt/tmp
|
||||
mkdir /mnt/var
|
||||
|
||||
#
|
||||
# populate the directories
|
||||
#
|
||||
if [ ! -x /sys/compile/MINI/kernel ]
|
||||
then
|
||||
cat << EOM
|
||||
The MINI kernel does not exist, please create one.
|
||||
Here is an example config file:
|
||||
#
|
||||
# MINI -- A kernel to get FreeBSD on onto a disk.
|
||||
#
|
||||
machine "i386"
|
||||
cpu "I486_CPU"
|
||||
ident MINI
|
||||
maxusers 5
|
||||
|
||||
options INET # needed for _tcp _icmpstat _ipstat
|
||||
# _udpstat _tcpstat _udb
|
||||
options FFS #Berkeley Fast File System
|
||||
options FAT_CURSOR #block cursor in syscons or pccons
|
||||
options SCSI_DELAY=15 #Be pessimistic about Joe SCSI device
|
||||
options NCONS=2 #1 virtual consoles
|
||||
options USERCONFIG #Allow user configuration with -c XXX
|
||||
|
||||
config kernel root on sd0 swap on sd0 and sd1 dumps on sd0
|
||||
|
||||
controller isa0
|
||||
controller pci0
|
||||
|
||||
controller fdc0 at isa? port "IO_FD1" bio irq 6 drq 2 vector fdintr
|
||||
disk fd0 at fdc0 drive 0
|
||||
|
||||
controller ncr0
|
||||
|
||||
controller scbus0
|
||||
|
||||
device sc0 at isa? port "IO_KBD" tty irq 1 vector scintr
|
||||
device npx0 at isa? port "IO_NPX" irq 13 vector npxintr
|
||||
|
||||
device sd0
|
||||
device sd1
|
||||
device sd2
|
||||
|
||||
device st0
|
||||
|
||||
pseudo-device loop # required by INET
|
||||
pseudo-device gzip # Exec gzipped a.out's
|
||||
EOM
|
||||
exit 1
|
||||
fi
|
||||
|
||||
cp -f /sys/compile/MINI/kernel /mnt
|
||||
|
||||
gzip -c -best /sbin/init > /mnt/sbin/init
|
||||
gzip -c -best /sbin/fsck > /mnt/sbin/fsck
|
||||
gzip -c -best /sbin/mount > /mnt/sbin/mount
|
||||
gzip -c -best /sbin/halt > /mnt/sbin/halt
|
||||
gzip -c -best /sbin/restore > /mnt/sbin/restore
|
||||
|
||||
gzip -c -best /bin/sh > /mnt/bin/sh
|
||||
gzip -c -best /bin/sync > /mnt/bin/sync
|
||||
|
||||
cp /root/.profile /mnt/root
|
||||
|
||||
cp -f /dev/MAKEDEV /mnt/dev
|
||||
chmod 755 /mnt/dev/MAKEDEV
|
||||
|
||||
chmod 500 /mnt/sbin/init
|
||||
chmod 555 /mnt/sbin/fsck /mnt/sbin/mount /mnt/sbin/halt
|
||||
chmod 555 /mnt/bin/sh /mnt/bin/sync
|
||||
chmod 6555 /mnt/sbin/restore
|
||||
|
||||
#
|
||||
# create the devices nodes
|
||||
#
|
||||
cd /mnt/dev
|
||||
./MAKEDEV std
|
||||
./MAKEDEV sd0
|
||||
./MAKEDEV sd1
|
||||
./MAKEDEV sd2
|
||||
./MAKEDEV st0
|
||||
./MAKEDEV pty0
|
||||
cd /
|
||||
|
||||
#
|
||||
# create minimum filesystem table
|
||||
#
|
||||
cat > /mnt/etc/fstab <<EOM
|
||||
/dev/fd0a / ufs rw 1 1
|
||||
EOM
|
||||
|
||||
#
|
||||
# create minimum passwd file
|
||||
#
|
||||
cat > /mnt/etc/passwd <<EOM
|
||||
root:*:0:0:Charlie &:/root:/bin/sh
|
||||
EOM
|
||||
|
||||
cat > /mnt/etc/master.passwd <<EOM
|
||||
root::0:0::0:0:Charlie &:/root:/bin/sh
|
||||
EOM
|
||||
|
||||
chmod 600 /mnt/etc/master.passwd
|
||||
chmod 644 /mnt/etc/passwd
|
||||
/usr/sbin/pwd_mkdb -d/mnt/etc /mnt/etc/master.passwd
|
||||
|
||||
#
|
||||
# umount the floppy and inform the user
|
||||
#
|
||||
/sbin/umount /mnt
|
||||
</verb></tscreen>
|
||||
|
||||
<sect2><heading>After the Disaster</heading>
|
||||
<p>The key question is: did your hardware survive? You
|
||||
have been doing regular backups so there is no need to worry
|
||||
about the software.
|
||||
|
||||
<p>If the hardware has been damaged. First, replace
|
||||
those parts that have been damaged.
|
||||
|
||||
<p>If your hardware is okay, check your floppies. If you
|
||||
are using a custom boot floppy, boot single-user (type "-s" at
|
||||
the "boot:" prompt). Skip the following paragraph.
|
||||
|
||||
<p>If you are using the boot.flp and fixit.flp floppies,
|
||||
keep reading. Insert the boot.flp floppy in the first floppy drive
|
||||
and boot the computer. The original install menu will be displayed
|
||||
on the screen. Select the "Fixit--Repair mode with CDROM or floppy."
|
||||
option. Insert the fixit.flp when prompted. <tt>restore</tt> and
|
||||
the other programs that you need are located in <tt>/mnt2/stand</tt>.
|
||||
|
||||
<p>Recover each filesystem separately.
|
||||
|
||||
<p>Try to <tt>mount(8) (e.g. mount /dev/sd0a /mnt) </tt>
|
||||
the root partition of your first disk. If the disklabel was
|
||||
damaged, use <tt>disklabel(8)</tt> to re-partition and label the
|
||||
disk to match the label that your printed and saved. Use
|
||||
<tt>newfs(8)</tt> to re-create the filesystems. Re-mount the
|
||||
root partition of the floppy read-write ("<tt>mount -u -o rw
|
||||
/mnt</tt>"). Use your backup program and backup tapes to recover
|
||||
the data for this filesystem (e.g. <tt>restore vrf
|
||||
/dev/st0</tt>). Unmount the filesystem (e.g. <tt>umount
|
||||
/mnt</tt>) Repeat for each filesystem that was damaged.
|
||||
|
||||
<p>Once your system is running, backup your data onto new
|
||||
tapes. Whatever caused the crash or data loss may strike again.
|
||||
An another hour spent now, may save you from further distress later.
|
||||
|
||||
<sect2><heading>* I did not prepare for the Disaster, What Now?</heading>
|
||||
|
||||
30
handbook/disks.sgml
Normal file
30
handbook/disks.sgml
Normal file
|
|
@ -0,0 +1,30 @@
|
|||
<!-- This is an SGML document in the linuxdoc DTD describing
|
||||
Disks and FreeBSD. By David O'Brien, 1998.
|
||||
|
||||
$Id: disks.sgml,v 1.1 1998-04-30 10:31:02 obrien Exp $
|
||||
|
||||
The FreeBSD Documentation Project
|
||||
|
||||
<!DOCTYPE linuxdoc PUBLIC "-//FreeBSD//DTD linuxdoc//EN">
|
||||
|
||||
<article>
|
||||
<title> Disks and FreeBSD
|
||||
<author> David O'Brien <tt/obrien@cs.ucdavis.edu/
|
||||
<date> 26 April 1998, (c) 1998
|
||||
|
||||
<abstract> This document describes disk administration task under
|
||||
FreeBSD. It tells how to set up disks and bring them online.
|
||||
</abstract>
|
||||
|
||||
<toc>
|
||||
-->
|
||||
|
||||
<chapt><heading>Disks<label id="disks"></heading>
|
||||
|
||||
<p><em>Contributed by &a.obrien;<newline>26 April 1998</em>
|
||||
|
||||
<sect><heading> * Using systinstall</heading>
|
||||
<sect><heading> * Using command line utilities</heading>
|
||||
<sect1><heading> * Creating Slices</heading>
|
||||
<sect1><heading> * Dedicated</heading>
|
||||
|
||||
|
|
@ -1,4 +1,4 @@
|
|||
<!-- $Id: handbook.sgml,v 1.83 1998-03-24 00:00:04 jkh Exp $ -->
|
||||
<!-- $Id: handbook.sgml,v 1.84 1998-04-30 10:31:02 obrien Exp $ -->
|
||||
<!-- The FreeBSD Documentation Project -->
|
||||
|
||||
<!DOCTYPE linuxdoc PUBLIC "-//FreeBSD//DTD linuxdoc//EN" [
|
||||
|
|
@ -93,7 +93,12 @@ name="FreeBSD FTP server"> or one of the numerous
|
|||
|
||||
&printing;
|
||||
|
||||
&disks;
|
||||
|
||||
&backups;
|
||||
|
||||
"as;
|
||||
|
||||
<chapt><heading>The X Window System</heading>
|
||||
<p>Pending the completion of this section, please refer to
|
||||
documentation supplied by the <url url="http://www.xfree86.org/"
|
||||
|
|
|
|||
544
handbook/hw.sgml
544
handbook/hw.sgml
|
|
@ -1,4 +1,4 @@
|
|||
<!-- $Id: hw.sgml,v 1.81 1998-03-24 01:00:59 jkh Exp $ -->
|
||||
<!-- $Id: hw.sgml,v 1.82 1998-04-30 10:31:04 obrien Exp $ -->
|
||||
<!-- The FreeBSD Documentation Project -->
|
||||
|
||||
<!--
|
||||
|
|
@ -250,7 +250,8 @@ Slippery when wet. Beware of dog.
|
|||
<sect2><heading>* EISA</heading>
|
||||
<sect2><heading>* VLB</heading>
|
||||
<sect2><heading>PCI<label id="hw:mb:pci"></heading>
|
||||
<p><em>Contributed by &a.rgrimes;.<newline>25 April 1995.</em></p>
|
||||
<p><em>Contributed by &a.obrien; from postings by &a.rgrimes;.
|
||||
<newline>25 April 1995.</em></p>
|
||||
<p><em>Continuing updates by &a.jkh;.</em><newline>Last update on
|
||||
<em>26 August 1996.</em></p>
|
||||
<p>Of the Intel PCI chip sets, the following list describes
|
||||
|
|
@ -515,7 +516,7 @@ This drive will read and write QIC-150 (DC6150), QIC-250
|
|||
(DC6250), and QIC-525 (DC6525) tapes as well.
|
||||
<p>Data transfer rate is 350kB/s using <tt>dump(8)</tt>.
|
||||
Rates of 530kB/s have been reported when using <ref
|
||||
id="hw:storage:amanda" name="Amanda">
|
||||
id="backups:programs:amanda" name="Amanda">
|
||||
<p>Production of this drive has been discontinued.
|
||||
<p>The SCSI bus connector on this tape drive is reversed
|
||||
from that on most other SCSI devices. Make sure that you have
|
||||
|
|
@ -1009,543 +1010,6 @@ Wangtek 6200</heading>
|
|||
|
||||
<sect1><heading>* Other</heading>
|
||||
|
||||
<sect1><heading>* Adding and reconfiguring disks</heading>
|
||||
<sect1><heading> Tapes and backups<label id="hw:storage:tapebackups"></heading>
|
||||
<sect2><heading>* What about backups to floppies?</heading>
|
||||
<sect2><heading> Tape Media</heading>
|
||||
<sect3><heading><label id="hw:storage:tapebackups:4mm">
|
||||
4mm (DDS: Digital Data Storage)</heading>
|
||||
<!--gen-->
|
||||
<p>4mm tapes are replacing QIC as the workstation backup
|
||||
media of choice. This trend accelerated greatly when Conner
|
||||
purchased Archive, a leading manufacturer of QIC drives, and then
|
||||
stopped production of QIC drives. 4mm drives are small and quiet
|
||||
but do not have the reputation for reliability that is enjoyed by 8mm drives.
|
||||
The cartridges are less expensive and smaller (3 x 2 x 0.5
|
||||
inches, 76 x 51 x 12 mm) than 8mm cartridges. 4mm, like 8mm, has
|
||||
comparatively short head life for the same reason, both use
|
||||
helical scan.
|
||||
|
||||
<!--spec-->
|
||||
<p>Data thruput on these drives starts ~150kB/s, peaking
|
||||
at ~500kB/s. Data capacity starts at 1.3 GB and ends at 2.0 GB.
|
||||
Hardware compression, available with most of these drives,
|
||||
approximately doubles the capacity. Multi-drive tape library
|
||||
units can have 6 drives in a single cabinet with automatic tape
|
||||
changing. Library capacities reach 240 GB.
|
||||
|
||||
<!--tech-->
|
||||
<p>4mm drives, like 8mm drives, use helical-scan. All
|
||||
the benefits and drawbacks of helical-scan apply to both 4mm and
|
||||
8mm drives.
|
||||
|
||||
<p>Tapes should be retired from use after 2,000 passes or
|
||||
100 full backups.
|
||||
|
||||
<sect3><heading><label id="hw:storage:tapebackups:8mm">
|
||||
8mm (Exabyte)</heading>
|
||||
|
||||
<!--gen-->
|
||||
<p>8mm tapes are the most common SCSI tape drives; they
|
||||
are the best choice of exchanging tapes. Nearly every site has
|
||||
an exabyte 2 GB 8mm tape drive. 8mm drives are reliable,
|
||||
convenient and quiet. Cartridges are inexpensive and small (4.8 x
|
||||
3.3 x 0.6 inches; 122 x 84 x 15 mm). One downside of 8mm tape is
|
||||
relatively short head and tape life due to the high rate of
|
||||
relative motion of the tape across the heads.
|
||||
|
||||
<!--spec-->
|
||||
<p>Data thruput ranges from ~250kB/s to ~500kB/s. Data
|
||||
sizes start at 300 MB and go up to 7 GB. Hardware compression,
|
||||
available with most of these drives, approximately doubles the
|
||||
capacity. These drives are available as single units or
|
||||
multi-drive tape libraries with 6 drives and 120 tapes in a
|
||||
single cabinet. Tapes are changed automatically by the unit.
|
||||
Library capacities reach 840+ GB.
|
||||
|
||||
<!--tech-->
|
||||
<p>Data is recorded onto the tape using helical-scan, the
|
||||
heads are positioned at an angle to the media (approximately 6
|
||||
degrees). The tape wraps around 270 degrees of the spool that
|
||||
holds the heads. The spool spins while the tape slides over the
|
||||
spool. The result is a high density of data and closely packed
|
||||
tracks that angle across the tape from one edge to the other.
|
||||
|
||||
|
||||
<sect3><heading><label id="hw:storage:tapebackups:qic">
|
||||
QIC</heading>
|
||||
<!--gen-->
|
||||
<p>QIC-150 tapes and drives are, perhaps, the most common
|
||||
tape drive and media around. QIC tape drives are the least
|
||||
expensive "serious" backup drives. The downside is the cost of
|
||||
media. QIC tapes are expensive compared to 8mm or 4mm tapes, up
|
||||
to 5 times the price per GB data storage. But, if your needs can
|
||||
be satisfied with a half-dozen tapes, QIC may be the correct
|
||||
choice. QIC is the <em>most</em> common tape drive. Every site
|
||||
has a QIC drive of some density or another. Therein lies the
|
||||
rub, QIC has a large number of densities on physically similar
|
||||
(sometimes identical) tapes. QIC drives are not quiet. These
|
||||
drives audibly seek before they begin to record data and are
|
||||
clearly audible whenever reading, writing or seeking. QIC tapes
|
||||
measure (6 x 4 x 0.7 inches; 15.2 x 10.2 x 1.7 mm). <ref
|
||||
id="hw:storage:tapebackups:mini" name="Mini-cartridges">, which also
|
||||
use 1/4" wide tape are discussed separately. Tape libraries and
|
||||
changers are not available.
|
||||
|
||||
<!--spec-->
|
||||
<p>Data thruput ranges from ~150kB/s to ~500kB/s. Data
|
||||
capacity ranges from 40 MB to 15 GB. Hardware compression is
|
||||
available on many of the newer QIC drives. QIC drives are less
|
||||
frequently installed; they are being supplanted by DAT drives.
|
||||
|
||||
<!--tech-->
|
||||
<p>Data is recorded onto the tape in tracks. The tracks
|
||||
run along the long axis of the tape media from one end to the
|
||||
other. The number of tracks, and therefore the width of a track,
|
||||
varies with the tape's capacity. Most if not all newer drives
|
||||
provide backward-compatibility at least for reading (but often
|
||||
also for writing). QIC has a good reputation regarding the
|
||||
safety of the data (the mechanics are simpler and more robust
|
||||
than for helical scan drives).
|
||||
|
||||
<p>Tapes should be retired from use after 5,000 backups.
|
||||
|
||||
<sect3><heading><label id="hw:storage:tapebackups:mini">
|
||||
* Mini-Cartridge</heading>
|
||||
|
||||
<sect3><heading><label id="hw:storage:tapebackups:dlt">
|
||||
DLT</heading>
|
||||
<!--gen-->
|
||||
<p>DLT has the fastest data transfer rate of all the drive
|
||||
types listed here. The 1/2" (12.5mm) tape is contained in a
|
||||
single spool cartridge (4 x 4 x 1 inches; 100 x 100 x 25 mm). The
|
||||
cartridge has a swinging gate along one entire side of the
|
||||
cartridge. The drive mechanism opens this gate to extract the
|
||||
tape leader. The tape leader has an oval hole in it which the
|
||||
drive uses to "hook" the tape. The take-up spool is located
|
||||
inside the tape drive. All the other tape cartridges listed here
|
||||
(9 track tapes are the only exception) have both the supply and
|
||||
take-up spools located inside the tape cartridge itself.
|
||||
|
||||
<!--spec-->
|
||||
Data thruput is approximately 1.5MB/s, three times the
|
||||
thruput of 4mm, 8mm, or QIC tape drives. Data capacities range
|
||||
from 10GB to 20GB for a single drive. Drives are available in
|
||||
both multi-tape changers and multi-tape, multi-drive tape
|
||||
libraries containing from 5 to 900 tapes over 1 to 20 drives,
|
||||
providing from 50GB to 9TB of storage.
|
||||
|
||||
<!--tech-->
|
||||
Data is recorded onto the tape in tracks parallel to the
|
||||
direction of travel (just like QIC tapes). Two tracks are written
|
||||
at once. Read/write head lifetimes are relatively long; once the
|
||||
tape stops moving, there is no relative motion between the heads
|
||||
and the tape.
|
||||
|
||||
<sect2><heading> Using a new tape for the first time</heading>
|
||||
<p>The first time that you try to read or write a new,
|
||||
completely blank tape, the operation will fail. The console
|
||||
messages should be similar to:
|
||||
<tscreen><verb>
|
||||
st0(ncr1:4:0): NOT READY asc:4,1
|
||||
st0(ncr1:4:0): Logical unit is in process of becoming ready
|
||||
</verb></tscreen>
|
||||
|
||||
The tape does not contain an Identifier Block (block number
|
||||
0). All QIC tape drives since the adoption of QIC-525 standard
|
||||
write an Identifier Block to the tape. There are two
|
||||
solutions:
|
||||
<p><tt>mt fsf 1</tt> causes the tape drive to write an
|
||||
Identifier Block to the tape.
|
||||
<p>Use the front panel button to eject the tape.
|
||||
<p>Re-insert the tape and <tt>dump(8)</tt> data to the
|
||||
tape.
|
||||
<p><tt>dump(8)</tt> will report <tt>DUMP: End of tape
|
||||
detected</tt> and the console will show: <tt>HARDWARE FAILURE
|
||||
info:280 asc:80,96</tt>
|
||||
<p>rewind the tape using: <tt>mt rewind</tt>
|
||||
|
||||
<p>Subsequent tape operations are successful.
|
||||
|
||||
<sect2><heading> Backup Programs</heading>
|
||||
<p>The three major programs are <tt>dump(8)</tt>,
|
||||
<tt>tar(1)</tt>, and <tt>cpio(1)</tt>.
|
||||
|
||||
<sect3><heading> Dump and Restore</heading>
|
||||
<!--gen-->
|
||||
<p><tt>dump(8)</tt> and <tt>restore(8)</tt> are the
|
||||
traditional Unix backup programs. They operate on the drive as a
|
||||
collection of disk blocks, below the abstractions of files, links
|
||||
and directories that are created by the filesystems.
|
||||
<tt>dump(8)</tt> backs up devices, entire filesystems, not parts
|
||||
of a filesystem and not directory trees that span more than one
|
||||
filesystem, using either soft links <tt>ln(1)</tt> or mounting
|
||||
one filesystem onto another. <tt>dump(8)</tt> does not write
|
||||
files and directories to tape, but rather writes the data blocks
|
||||
that are the building blocks of files and directories.
|
||||
<tt>dump(8)</tt> has quirks that remain from its early days in
|
||||
Version 6 of ATT Unix (circa 1975). The default parameters are
|
||||
suitable for 9-track tapes (6250 bpi), not the high-density media
|
||||
available today (up to 62,182 ftpi). These defaults must be
|
||||
overridden on the command line to utilize the capacity of current
|
||||
tape drives.
|
||||
|
||||
<p><tt>rdump(8)</tt> and <tt>rrestore(8)</tt> backup data
|
||||
across the network to a tape drive attached to another computer.
|
||||
Both programs rely upon <tt>rcmd(3)</tt> and <tt>ruserok(3)</tt>
|
||||
to access the remote tape drive. Therefore, the user performing
|
||||
the backup must have <tt>rhosts</tt> access to the remote
|
||||
computer. The arguments to <tt>rdump(8)</tt> and
|
||||
<tt>rrestore(8)</tt> must suitable to use on the remote computer.
|
||||
(e.g. When <tt>rdump</tt>'ing from a FreeBSD computer to an
|
||||
Exabyte tape drive connected to a Sun called komodo, use: <tt>/sbin/rdump
|
||||
0dsbfu 54000 13000 126 komodo:/dev/nrst8 /dev/rsd0a 2>&1</tt>)
|
||||
Beware: there are security implications to allowing
|
||||
<tt>rhosts</tt> commands. Evaluate your situation carefully.
|
||||
|
||||
|
||||
|
||||
<sect3><heading> Tar</heading>
|
||||
<!--gen-->
|
||||
<p><tt>tar(1)</tt> also dates back to Version 6 of ATT
|
||||
Unix (circa 1975). <tt>tar(1)</tt> operates in cooperation with
|
||||
the filesystem; <tt>tar(1)</tt> writes files and directories to
|
||||
tape. <tt>tar(1)</tt> does not support the full range of options
|
||||
that are available from <tt>cpio(1)</tt>, but <tt>tar(1)</tt>
|
||||
does not require the unusual command pipeline that
|
||||
<tt>cpio(1)</tt> uses.
|
||||
|
||||
<p>Most versions of <tt>tar(1)</tt> do not support backups across the
|
||||
network. The GNU version of <tt>tar(1)</tt>, which FreeBSD utilizes, supports
|
||||
remote devices using the same syntax as <tt>rdump</tt>. To <tt>tar(1)</tt>
|
||||
to an Exabyte tape drive connected to a Sun called komodo, use:
|
||||
<tt>/usr/bin/tar cf komodo:/dev/nrst8 . 2>&1</tt>.
|
||||
For versions without remote device support, you can use a pipeline
|
||||
and <tt>rsh(1)</tt> to send the
|
||||
data to a remote tape drive. (XXX add an example command)
|
||||
|
||||
<sect3><heading> Cpio</heading>
|
||||
<!--gen-->
|
||||
<p><tt>cpio(1)</tt> is the original Unix file interchange
|
||||
tape program for magnetic media. <tt>cpio(1)</tt> has options (among
|
||||
many others) to perform byte-swapping, write a number of
|
||||
different archives format, and pipe the data to other programs.
|
||||
This last feature makes <tt>cpio(1)</tt> and excellent choice for
|
||||
installation media. <tt>cpio(1)</tt> does not know how to walk
|
||||
the directory tree and a list of files must be provided thru <tt>STDIN</tt>.
|
||||
|
||||
<p><tt>cpio(1)</tt> does not support backups across the
|
||||
network. You can use a pipeline and <tt>rsh(1)</tt> to send the
|
||||
data to a remote tape drive. (XXX add an example command)
|
||||
|
||||
<sect3><heading> Pax</heading>
|
||||
<!--gen-->
|
||||
|
||||
<p><tt>pax(1)</tt> is IEEE/POSIX's answer to <tt>tar</tt> and
|
||||
<tt>cpio</tt>. Over the years the various versions of <tt>tar</tt> and
|
||||
<tt>cpio</tt> have gotten slightly incompatible. So rather than fight it
|
||||
out to fully standardize them, POSIX created a new archive utility.
|
||||
<tt>pax</tt> attempts to read and write many of the various cpio and tar
|
||||
formats, plus new formats of its own. Its command set more resembles
|
||||
<tt>cpio</tt> than <tt>tar</tt>.
|
||||
|
||||
|
||||
<sect3><heading><label id="hw:storage:amanda"><htmlurl
|
||||
url="http://www.freebsd.org/ports/misc.html#amanda-2.2.6.5"
|
||||
name="Amanda"></heading>
|
||||
<p>Amanda (Advanced Maryland Network Disk Archiver) is a
|
||||
client/server backup system, rather than a single program. An
|
||||
Amanda server will backup to a single tape drive any number of
|
||||
computers that have Amanda clients and network communications
|
||||
with the Amanda server. A common problem at locations with a
|
||||
number of large disks is the length of time required to backup to
|
||||
data directly to tape exceeds the amount of time available for
|
||||
the task. Amanda solves this problem. Amanda can use a "holding
|
||||
disk" to backup several filesystems at the same time. Amanda
|
||||
creates "archive sets": a group of tapes used over a period of
|
||||
time to create full backups of all the filesystems listed in
|
||||
Amanda's configuration file. The "archive set" also contains
|
||||
nightly incremental (or differential) backups of all the
|
||||
filesystems. Restoring a damaged filesystem requires the most
|
||||
recent full backup and the incremental backups.
|
||||
|
||||
<p>The configuration file provides fine control backups
|
||||
and the network traffic that Amanda generates. Amanda will use
|
||||
any of the above backup programs to write the data to tape.
|
||||
Amanda is available as either a port or a package, it is not
|
||||
installed by default.
|
||||
|
||||
<sect3><heading> Do nothing</heading>
|
||||
<p>"Do nothing" is not a computer program, but it is the
|
||||
most widely used backup strategy. There are no initial costs.
|
||||
There is no backup schedule to follow. Just say no. If
|
||||
something happens to your data, grin and bear it!
|
||||
|
||||
<p>If your time and your data is worth little to nothing,
|
||||
then "Do nothing" is the most suitable backup program for your
|
||||
computer. But beware, Unix is a useful tool, you may find that
|
||||
within six months you have a collection of files that are
|
||||
valuable to you.
|
||||
|
||||
<p>"Do nothing" is the correct backup method for
|
||||
<tt>/usr/obj</tt> and other directory trees that can be exactly
|
||||
recreated by your computer. An example is the files that
|
||||
comprise these handbook pages-they have been generated from
|
||||
<tt>SGML</tt> input files. Creating backups of these
|
||||
<tt>HTML</tt> files is not necessary. The <tt>SGML</tt> source
|
||||
files are backed up regularly.
|
||||
|
||||
<sect3><heading> Which Backup Program is Best?</heading>
|
||||
<p><tt>dump(8)</tt> <em>Period.</em> Elizabeth D. Zwicky
|
||||
torture tested all the backup programs discussed here. The clear
|
||||
choice for preserving all your data and all the peculiarities of
|
||||
Unix filesystems is <tt>dump(8)</tt>. Elizabeth created
|
||||
filesystems containing a large variety of unusual conditions (and
|
||||
some not so unusual ones) and tested each program by do a backup
|
||||
and restore of that filesystems. The peculiarities included:
|
||||
files with holes, files with holes and a block of nulls, files
|
||||
with funny characters in their names, unreadable and unwritable
|
||||
files, devices, files that change size during the backup, files
|
||||
that are created/deleted during the backup and more. She
|
||||
presented the results at LISA V in Oct. 1991.
|
||||
|
||||
<sect2><heading>Emergency Restore Procedure</heading>
|
||||
<sect3><heading> Before the Disaster</heading>
|
||||
<p>There are only four steps that you need to perform in
|
||||
preparation for any disaster that may occur.
|
||||
|
||||
<p>First, print the disklabel from each of your disks
|
||||
(<tt>e.g. disklabel sd0 | lpr</tt>), your filesystem table
|
||||
(<tt>/etc/fstab</tt>) and all boot messages, two copies of each.
|
||||
|
||||
<p>Second, determine the boot and fixit floppies
|
||||
(boot.flp and fixit.flp) have all your devices. The easiest way
|
||||
to check is to reboot your machine with the boot floppy in the
|
||||
floppy drive and check the boot messages. If all your devices
|
||||
are listed and functional, skip on to step three.
|
||||
|
||||
<p>Otherwise, you have to create two custom bootable
|
||||
floppies which has a kernel that can mount your all of your disks
|
||||
and access your tape drive. These floppies must contain:
|
||||
<tt>fdisk(8)</tt>, <tt>disklabel(8)</tt>, <tt>newfs(8)</tt>,
|
||||
<tt>mount(8)</tt>, and whichever backup program you use. These
|
||||
programs must be statically linked. If you use <tt>dump(8)</tt>,
|
||||
the floppy must contain <tt>restore(8)</tt>.
|
||||
|
||||
<p>Third, create backup tapes regularly.
|
||||
Any changes that you make after your last backup may be
|
||||
irretrievably lost. Write-protect the backup tapes.
|
||||
|
||||
<p>Fourth, test the floppies (either boot.flp and
|
||||
fixit.flp or the two custom bootable floppies you made in step
|
||||
two.) and backup tapes. Make notes of the procedure. Store
|
||||
these notes with the bootable floppy, the printouts and the
|
||||
backup tapes. You will be so distraught when restoring that the
|
||||
notes may prevent you from destroying your backup tapes (How? In
|
||||
place of <tt>tar xvf /dev/rst0</tt>, you might accidently type
|
||||
<tt> tar cvf /dev/rst0</tt> and over-write your backup tape).
|
||||
|
||||
<p>For an added measure of security, make bootable
|
||||
floppies and two backup tapes each time. Store one of each at a
|
||||
remote location. A remote location is NOT the basement of the
|
||||
same office building. A number of firms in the World Trade Center
|
||||
learned this lesson the hard way. A remote location should be
|
||||
physically separated from your computers and disk drives by a
|
||||
significant distance.
|
||||
|
||||
<p>An example script for creating a bootable floppy:
|
||||
<tscreen><verb>
|
||||
#!/bin/sh
|
||||
#
|
||||
# create a restore floppy
|
||||
#
|
||||
# format the floppy
|
||||
#
|
||||
PATH=/bin:/sbin:/usr/sbin:/usr/bin
|
||||
|
||||
fdformat -q fd0
|
||||
if [ $? -ne 0 ]
|
||||
then
|
||||
echo "Bad floppy, please use a new one"
|
||||
exit 1
|
||||
fi
|
||||
|
||||
# place boot blocks on the floppy
|
||||
#
|
||||
disklabel -w -B -b /usr/mdec/fdboot -s /usr/mdec/bootfd /dev/rfd0c fd1440
|
||||
|
||||
#
|
||||
# newfs the one and only partition
|
||||
#
|
||||
newfs -t 2 -u 18 -l 1 -c 40 -i 5120 -m 5 -o space /dev/rfd0a
|
||||
|
||||
#
|
||||
# mount the new floppy
|
||||
#
|
||||
mount /dev/fd0a /mnt
|
||||
|
||||
#
|
||||
# create required directories
|
||||
#
|
||||
mkdir /mnt/dev
|
||||
mkdir /mnt/bin
|
||||
mkdir /mnt/sbin
|
||||
mkdir /mnt/etc
|
||||
mkdir /mnt/root
|
||||
mkdir /mnt/mnt # for the root partition
|
||||
mkdir /mnt/tmp
|
||||
mkdir /mnt/var
|
||||
|
||||
#
|
||||
# populate the directories
|
||||
#
|
||||
if [ ! -x /sys/compile/MINI/kernel ]
|
||||
then
|
||||
cat << EOM
|
||||
The MINI kernel does not exist, please create one.
|
||||
Here is an example config file:
|
||||
#
|
||||
# MINI -- A kernel to get FreeBSD on onto a disk.
|
||||
#
|
||||
machine "i386"
|
||||
cpu "I486_CPU"
|
||||
ident MINI
|
||||
maxusers 5
|
||||
|
||||
options INET # needed for _tcp _icmpstat _ipstat
|
||||
# _udpstat _tcpstat _udb
|
||||
options FFS #Berkeley Fast File System
|
||||
options FAT_CURSOR #block cursor in syscons or pccons
|
||||
options SCSI_DELAY=15 #Be pessimistic about Joe SCSI device
|
||||
options NCONS=2 #1 virtual consoles
|
||||
options USERCONFIG #Allow user configuration with -c XXX
|
||||
|
||||
config kernel root on sd0 swap on sd0 and sd1 dumps on sd0
|
||||
|
||||
controller isa0
|
||||
controller pci0
|
||||
|
||||
controller fdc0 at isa? port "IO_FD1" bio irq 6 drq 2 vector fdintr
|
||||
disk fd0 at fdc0 drive 0
|
||||
|
||||
controller ncr0
|
||||
|
||||
controller scbus0
|
||||
|
||||
device sc0 at isa? port "IO_KBD" tty irq 1 vector scintr
|
||||
device npx0 at isa? port "IO_NPX" irq 13 vector npxintr
|
||||
|
||||
device sd0
|
||||
device sd1
|
||||
device sd2
|
||||
|
||||
device st0
|
||||
|
||||
pseudo-device loop # required by INET
|
||||
pseudo-device gzip # Exec gzipped a.out's
|
||||
EOM
|
||||
exit 1
|
||||
fi
|
||||
|
||||
cp -f /sys/compile/MINI/kernel /mnt
|
||||
|
||||
gzip -c -best /sbin/init > /mnt/sbin/init
|
||||
gzip -c -best /sbin/fsck > /mnt/sbin/fsck
|
||||
gzip -c -best /sbin/mount > /mnt/sbin/mount
|
||||
gzip -c -best /sbin/halt > /mnt/sbin/halt
|
||||
gzip -c -best /sbin/restore > /mnt/sbin/restore
|
||||
|
||||
gzip -c -best /bin/sh > /mnt/bin/sh
|
||||
gzip -c -best /bin/sync > /mnt/bin/sync
|
||||
|
||||
cp /root/.profile /mnt/root
|
||||
|
||||
cp -f /dev/MAKEDEV /mnt/dev
|
||||
chmod 755 /mnt/dev/MAKEDEV
|
||||
|
||||
chmod 500 /mnt/sbin/init
|
||||
chmod 555 /mnt/sbin/fsck /mnt/sbin/mount /mnt/sbin/halt
|
||||
chmod 555 /mnt/bin/sh /mnt/bin/sync
|
||||
chmod 6555 /mnt/sbin/restore
|
||||
|
||||
#
|
||||
# create the devices nodes
|
||||
#
|
||||
cd /mnt/dev
|
||||
./MAKEDEV std
|
||||
./MAKEDEV sd0
|
||||
./MAKEDEV sd1
|
||||
./MAKEDEV sd2
|
||||
./MAKEDEV st0
|
||||
./MAKEDEV pty0
|
||||
cd /
|
||||
|
||||
#
|
||||
# create minimum filesystem table
|
||||
#
|
||||
cat > /mnt/etc/fstab <<EOM
|
||||
/dev/fd0a / ufs rw 1 1
|
||||
EOM
|
||||
|
||||
#
|
||||
# create minimum passwd file
|
||||
#
|
||||
cat > /mnt/etc/passwd <<EOM
|
||||
root:*:0:0:Charlie &:/root:/bin/sh
|
||||
EOM
|
||||
|
||||
cat > /mnt/etc/master.passwd <<EOM
|
||||
root::0:0::0:0:Charlie &:/root:/bin/sh
|
||||
EOM
|
||||
|
||||
chmod 600 /mnt/etc/master.passwd
|
||||
chmod 644 /mnt/etc/passwd
|
||||
/usr/sbin/pwd_mkdb -d/mnt/etc /mnt/etc/master.passwd
|
||||
|
||||
#
|
||||
# umount the floppy and inform the user
|
||||
#
|
||||
/sbin/umount /mnt
|
||||
</verb></tscreen>
|
||||
|
||||
<sect3><heading>After the Disaster</heading>
|
||||
<p>The key question is: did your hardware survive? You
|
||||
have been doing regular backups so there is no need to worry
|
||||
about the software.
|
||||
|
||||
<p>If the hardware has been damaged. First, replace
|
||||
those parts that have been damaged.
|
||||
|
||||
<p>If your hardware is okay, check your floppies. If you
|
||||
are using a custom boot floppy, boot single-user (type "-s" at
|
||||
the "boot:" prompt). Skip the following paragraph.
|
||||
|
||||
<p>If you are using the boot.flp and fixit.flp floppies,
|
||||
keep reading. Insert the boot.flp floppy in the first floppy drive
|
||||
and boot the computer. The original install menu will be displayed
|
||||
on the screen. Select the "Fixit--Repair mode with CDROM or floppy."
|
||||
option. Insert the fixit.flp when prompted. <tt>restore</tt> and
|
||||
the other programs that you need are located in <tt>/mnt2/stand</tt>.
|
||||
|
||||
<p>Recover each filesystem separately.
|
||||
|
||||
<p>Try to <tt>mount(8) (e.g. mount /dev/sd0a /mnt) </tt>
|
||||
the root partition of your first disk. If the disklabel was
|
||||
damaged, use <tt>disklabel(8)</tt> to re-partition and label the
|
||||
disk to match the label that your printed and saved. Use
|
||||
<tt>newfs(8)</tt> to re-create the filesystems. Re-mount the
|
||||
root partition of the floppy read-write ("<tt>mount -u -o rw
|
||||
/mnt</tt>"). Use your backup program and backup tapes to recover
|
||||
the data for this filesystem (e.g. <tt>restore vrf
|
||||
/dev/st0</tt>). Unmount the filesystem (e.g. <tt>umount
|
||||
/mnt</tt>) Repeat for each filesystem that was damaged.
|
||||
|
||||
<p>Once your system is running, backup your data onto new
|
||||
tapes. Whatever caused the crash or data loss may strike again.
|
||||
An another hour spent now, may save you from further distress later.
|
||||
|
||||
<sect3><heading>* I did not prepare for the Disaster, What Now?</heading>
|
||||
|
||||
<sect><heading>* Other<label id="hw:other"></heading>
|
||||
<sect1><heading>* PCMCIA</heading>
|
||||
|
||||
|
|
|
|||
|
|
@ -1,4 +1,4 @@
|
|||
<!-- $Id: sections.sgml,v 1.28 1998-03-15 15:10:18 nik Exp $ -->
|
||||
<!-- $Id: sections.sgml,v 1.29 1998-04-30 10:31:05 obrien Exp $ -->
|
||||
<!-- The FreeBSD Documentation Project -->
|
||||
|
||||
<!-- Entities containing all the pieces of the handbook are -->
|
||||
|
|
@ -46,6 +46,8 @@
|
|||
<!ENTITY ports SYSTEM "ports.sgml">
|
||||
<!ENTITY ppp SYSTEM "ppp.sgml">
|
||||
<!ENTITY printing SYSTEM "printing.sgml">
|
||||
<!ENTITY backups SYSTEM "backups.sgml">
|
||||
<!ENTITY disks SYSTEM "disks.sgml">
|
||||
<!ENTITY quotas SYSTEM "quotas.sgml">
|
||||
<!ENTITY relnotes SYSTEM "relnotes.sgml">
|
||||
<!ENTITY routing SYSTEM "routing.sgml">
|
||||
|
|
|
|||
Loading…
Reference in a new issue